#!/usr/bin/env node

const http = require('http'),
      fs   = require('fs'),
      qs  = require('querystring'),
      log  = console.log;
let items = loadItems();
process.on('SIGINT',()=>{
  saveItems();
});

function loadItems(){
  log('loadItems');
  try{
    let items = fs.readFileSync('./12-items.txt').toString('utf8');
    items = JSON.parse(items);
    return items;
  }catch(e){
    return [];
  }
}



function saveItems(){
  log('saveItems');
  fs.writeFileSync('./12-items.txt',JSON.stringify(items));
}

let result = {
  status:200,
  reason:'OK',
};
http.createServer((req,res)=>{
  logRequest(req);
  
  if(req.url.slice(0,5) !== '/todo'){
    let html = fs.readFileSync('./12-todo.html').toString('utf8');
    if(req.url === '/'){
      res.end(html);
    }else if(req.url === '/12-todo.js'){
      fs.createReadStream('./12-todo.js').pipe(res);
    }else{
      res.end('not api request!');
    }
    return;
  }

  switch(req.method){
    case 'GET':
      select(req,res);
      break;

    case 'POST':
      insert(req,res);
      break;

    case 'PUT':
      update(req,res);
      break;

    case 'DELETE':
      remove(req,res);
      break;

    default:
      res.end(`${req.method} method not support`);
  }
}).listen(8080);

function select(req,res){
  result.data=items;
  res.end(JSON.stringify(result));
}
function insert(req,res){
  let data = '';
  req.on('data',chunk=>data += chunk);
  req.on('end',()=>{
    let item = qs.parse(data).item;
    if(item !== '' && typeof item !== 'undefined'){
      items.push(item);
      res.end(JSON.stringify(result));
    }else{
      result.status = 401;
      result.reason = 'item is empty';
      res.end(result);
    }
  });
}
function update(req,res){
  //get id
  let id = req.url.split(':')[1];
  //validate id
  //data type
  //value min=0,max=items.length
  
  //get item
  let data = '';
  req.on('data',chunk=>data += chunk);
  req.on('end',()=>{
    //update items[id] = item
    let item = qs.parse(data).item;
    if(item !== '' && typeof item !== 'undefined'){
      items[id] = item;
      res.end(JSON.stringify(result));
    }else{
      result.status = 401;
      result.reason = 'item is empty';
      res.end(result);
    }
  });

}
function remove(req,res){
  //get id
  let id = req.url.split(':')[1];
  //id not exist del all
  if(typeof id === 'undefined'){
    items = [];
    result.status = 200;
    result.reason = 'delete all success';
    res.end(JSON.stringify(result));
  }
  //id exist 
  //valide id
  //id is ok del items[id]
  items.splice(id,1);
  result.status = 200;
  result.reason = 'del success';
  res.end(JSON.stringify(result));
  

  res.end(req.method);
}
function logRequest(req){
  log(req.method);
  log(req.url);
  log(`HTTP/${req.httpVersion}`);
  log(req.headers);
  log();
}
